MOUNT VERNON — Dozens of police and sheriff’s detectives from Snohomish County joined a team of more than 100 investigators piecing together eight different crime scenes in Skagit County on Wednesday.

Police believe a lone killer on Tuesday took six people’s lives, including that of a Skagit County sheriff’s deputy, and injured four more people.

“We’re just trying to do what any good neighbor would do,” Snohomish County Sheriff John Lovick said. “It’s just devastating. Our prayers are with the families.”

The Snohomish County team included 30 detectives from 10 different agencies.

Tuesday’s carnage spread from a rural neighborhood in Alger onto busy I-5. It ended after a police pursuit when a suspect, Isaac Zamora, 28, of Alger, was arrested in Mount Vernon, officials said.

Among the four people injured was a Washington State Patrol trooper based in Marysville. Troy Giddings, with the commercial vehicle division, was shot in the arm during the chase. He is expected to recover.

“It’s just a horrific investigation,” Lovick said.

Police don’t yet know the motive for the attacks.

A Skagit County judge Wed­nesday ordered Zamora held on $5 million bail for investigation of six counts of first-degree murder and two counts of first-degree attempted murder.

The Snohomish County Multi-Agency Response Team, a special team of detectives from various agencies around the county, is providing assistance to the Northwest Unified Command, which is leading the investigation, Lovick said.

“They are something akin to an all-star team of homicide detectives,” Snohomish County deputy prosecutor Mark Roe said.

The team was formed about nine years ago to provide police departments with an objective, outside group to investigate officer-involved shootings and in-custody deaths, Snohomish Police Chief John Turner said. Over the years, the multiagency team has helped out during complex investigations. The trail of horror, death and violence in Skagit County is by far the biggest the team has helped investigate, Lovick said. It’s the first time the team has worked in Skagit County.

By putting a large number of detectives on the ground, police are hoping to process the crime scenes quickly, Turner said.

“Evidence deteriorates with time,” he said. “You want to do the best job you can in the time available.”

Zamora was booked early Wednesday morning into the Snohomish County Jail after he was interviewed by detectives in Everett, Everett police Sgt. Robert Goetz said. He was taken to court in Skagit County on Wednesday and then returned to the jail in Everett.

Zamora had been locked up in the Skagit County Jail until Aug. 6, serving time on a drug charge, said Chad Lewis, a state Department of Corrections spokesman.

The 28-year-old has a lengthy criminal record, he said. Zamora was categorized by the state as a “high-risk, nonviolent” offender. That means he was at a risk to commit more crimes, but state officials didn’t expect him to act violently.

His criminal history includes problems in north Snohomish County, court records show.

Arlington police arrested him in 2006 for marijuana possession and driving without a license. The case has continued to rattle around for two years. A Marysville Municipal Court judge ordered a warrant issued for Zamora’s arrest on May 21 after he failed to show up for hearings on the drug charge, documents show.

On May 15, Zamora was sentenced to six months in the Skagit County Jail, followed by a year under state supervision, Lewis said. He also was required to have a mental health screening after his release.

Zamora’s mother told reporters that her son is “desperately mentally ill” and had been living in the woods.

The suspect told corrections officials he was living in a trailer on his parent’s property in Alger, Lewis said.

As required, Zamora checked in twice with his corrections supervisor and on Aug. 21 submitted a urine sample that did not show signs he was using drugs or alcohol, Lewis said.

Zamora’s corrections supervisor was working to schedule a mental health screening, Lewis said. The effort was slowed because Zamora was applying for state-sponsored assistance to pay for the visit. The evaluation was further delayed by the lack of mental health resources in rural Skagit County, Lewis said.

High-ranking corrections officials spent time Wednesday conducting an investigation of Zamora’s records, Lewis said.

“Our review hasn’t found anything that would indicate that he was on the verge of committing something this heinous,” he said. “So far we haven’t seen any red flags that were missed.”

There are a large number of people with untreated mental health problems that end up in the criminal justice system, said Bill Jaquette, director of the Snohomish County Public Defender’s Office.

“As a society we still don’t do enough to provide services for people with mental health issues,” he said. “We see an awful lot of those people in our business.”

Jaquette’s office in 2007 defended a mentally ill man who eventually was sent to prison for life for an unprovoked attack on an Everett woman in her front yard.

Anthony Viscussi, 28, had previously been deemed a dangerously mental ill offender. He was under the supervision of the state Department of Corrections when he assaulted the woman in front of her 6-year-old son.

A judge determined that Viscussi was competent to stand trial. Despite the advice of his public defender, the Everett man pleaded guilty to the 2007 assault, securing himself a life sentence under the state’s three-strikes law.

Too often police are called upon as a last resort to deal with people suffering from mental health problems, Turner, the Snohomish police chief, said.

“The reality is that there is not sufficient mental health resources to deal effectively with the problem,” he said.

Violent crimes can be chaotic for families and friends of victims, said Jenny Wieland Ward, executive director of Families &Friends of Violent Crime Victims.

“In the aftermath of such a horrific crime, most victims must deal not only with the physical and emotional shock waves of the event, but are also thrust into the criminal justice system. We want those impacted by this tragedy to know they are not alone,” she said.

Lovick said he worked with Skagit County Sheriff Richard Grimstead when both were Washington State Patrol troopers.

He wanted to let his friend and colleague know the Snohomish County Sheriff’s Office will be there to help the Skagit County community grieve and heal.

A detachment of Snohomish County motorcycle deputies planned to escort the body of slain Skagit County deputy Anne Jackson, 40, as her funeral arrangements are made.

“For a fellow officer to be killed, we’re all just torn, emotionally and physically,” Lovick said. “It’s so unfortunate.”

The Associated Press contributed to this report.